Simple sentence structure 2

There is another kind of simple sentence in Chinese, but it's not exactly the same as English. Please read the following sentences and point out what's the difference.
我(wǒ)很(hěn)忙(mánɡ)。（I am busy.)[ps. the literally meaning of this sentence is I am very busy.)
我(wǒ)不(bù)忙(mánɡ)。( I am not busy.)